I got tired of copying a draft out of the agent and into a browser

I write a lot of software with coding agents now. At some point I got tired of the loop. The agent would draft a post. I would copy it. I would open the dashboard, pick accounts, paste, attach a file, click Publish, and feel like it was 2014 with extra steps. If the agent can write the sentence, it should be able to send the sentence.

So the HTTP API is not an add-on. After you sign in, you create a key under API Keys. The same publish path the dashboard uses is available over REST. List connected accounts, send content, optionally attach media URLs, optionally set per-platform copy, publish immediately or pass a time. If something can make an HTTP request with a Bearer token, it can post.

What it actually is

I am not going to dress this up as a marketplace. It is a key and a couple of endpoints. The docs live in the dashboard because that is where the key lives. There is no separate billed agent plan, and there is no MCP upsell page. If you can call https://postbroadcaster.com/api/external/posts, you are already on the real path.

Per-platform overrides use the same keys as the UI: FACEBOOK, INSTAGRAM, TWITTER, BLUESKY, and so on. That matters. I did not want the agent API to be a second, thinner product that cannot do the thing the composer can do. An agent that posts the LinkedIn version and the X version in one request is the whole point.

Scheduling works the same way. Set publish to false, pass scheduledFor, and the post sits in the queue like anything you picked from the calendar. I use this for changelog notes I do not want to babysit at 9am.

Two caveats that will bite you

Instagram still needs an image or a video. If your agent sends text only, that account will fail, and it should. Nostr accounts that rely on a browser extension still need a human in the loop to sign. A cron job cannot click the extension. If your agent hits those and they fail, that is the network, not a missing checkbox in the API.

Tokens also expire. When they do, the honest response is that the account needs reconnecting, not a retry loop that pretends the post went out. Same as the dashboard.

If you want the composer, use the composer. If you want a script to post on Thursday without opening a tab, use the API. I use both. The test I care about is whether they can disagree. They should not.